TF-003 Interact with Terraform modules — All Questions With Answers

Refer to the exhibit.

```hcl
module "vpc" {
  source = "terraform-aws-modules/vpc/aws"
  version = "3.19.0"
  name = "my-vpc"
  cidr = "10.0.0.0/16"
  azs  = ["us-east-1a", "us-east-1b"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]
}

output "vpc_id" {
  value = module.vpc.vpc_id
}
```

Refer to the exhibit.

```hcl
module "bucket" {
  source = "./modules/s3-bucket"
  bucket_name = "my-app-data"
}

resource "aws_s3_bucket_object" "config" {
  bucket = module.bucket.bucket_name
  key    = "config.json"
  source = "config.json"
}
```

The module at './modules/s3-bucket' contains:

```hcl
variable "bucket_name" {}
resource "aws_s3_bucket" "this" {
  bucket = var.bucket_name
}
output "bucket_name" {
  value = aws_s3_bucket.this.id
}
```

Refer to the exhibit.

```hcl
module "vpc" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "3.18.0"

  name = "my-vpc"
  cidr = "10.0.0.0/16"

  azs             = ["us-east-1a", "us-east-1b"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]

  enable_nat_gateway = true
  enable_vpn_gateway = true

  tags = {
    Terraform = "true"
    Environment = "dev"
  }
}
```

Refer to the exhibit.

```hcl
module "vpc" {
  source = "terraform-aws-modules/vpc/aws"
  version = "5.0.0"
  name = "my-vpc"
  cidr = "10.0.0.0/16"
  azs             = ["us-east-1a", "us-east-1b"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]
  enable_nat_gateway = true
  enable_vpn_gateway = false
}

output "vpc_id" {
  value = module.vpc.vpc_id
}
```

Refer to the exhibit.

```
Terraform will perform the following actions:

  # module.instances["web"].aws_instance.this will be created
  + resource "aws_instance" "this" {
      + ami                          = "ami-123456"
      + instance_type                = "t2.micro"
      + subnet_id                    = (known after apply)
      ...
    }

  # module.instances["app"].aws_instance.this will be created
  + resource "aws_instance" "this" {
      + ami                          = "ami-789012"
      + instance_type                = "t2.small"
      + subnet_id                    = (known after apply)
      ...
    }

Plan: 2 to add, 0 to change, 0 to destroy.
```

Refer to the exhibit.

```
module "networks" {
  source = "./modules/network"
  for_each = {
    dev  = "10.0.1.0/24"
    prod = "10.0.2.0/24"
  }
  cidr_block = each.value
  name       = each.key
}

resource "aws_flow_log" "example" {
  for_each = module.networks
  vpc_id   = each.value.vpc_id
  ...
}
```

Refer to the exhibit.

```
module "bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"
  bucket = "my-company-logs"
  acl    = "log-delivery-write"
}
```

Error during terraform plan:
```
Error: Unsupported argument
  on main.tf line 4, in module "bucket":
   4:   acl    = "log-delivery-write"
An argument named "acl" is not expected here.
```

Refer to the exhibit.
```hcl
module "networking" {
  source = "./modules/networking"
  vpc_cidr = "10.0.0.0/16"
}
```
The module in `./modules/networking` has `variables.tf`:
```hcl
variable "vpc_cidr" {
  description = "CIDR block for the VPC"
  type = string
}
variable "environment" {
  description = "Environment name"
  type = string
}
```

Refer to the exhibit.
```
$ terraform init
Initializing modules...
Downloading hashicorp/consul/aws 0.7.2 from registry.terraform.io...
- consul in .terraform/modules/consul

Initializing the backend...

Initializing provider plugins...
- Finding hashicorp/aws versions matching ">= 3.0"...
- Installing hashicorp/aws v3.74.0...
- Installed hashicorp/aws v3.74.0

Error: Unsupported terraform provider version

  on .terraform/modules/consul/main.tf line 1, in terraform:
   1: terraform {
   2:   required_providers {
   3:     aws = {
   4:       source  = "hashicorp/aws"
   5:       version = "~> 2.70"
   6:     }
   7:   }
   8: }

The root module requires hashicorp/aws >= 3.0, but the module requires ~> 2.70.
```

Refer to the exhibit.
```hcl
module "myapp" {
  source  = "terraform-aws-modules/vpc/aws"
  version = "~> 3.0"
  name = "my-vpc"
  cidr = "10.0.0.0/16"
  azs  = ["us-east-1a", "us-east-1b"]
  private_subnets = ["10.0.1.0/24", "10.0.2.0/24"]
  public_subnets  = ["10.0.101.0/24", "10.0.102.0/24"]
}
```
After running `terraform init`, the console shows it downloaded version 3.19.0 of the module. Why did it download that version?

Refer to the exhibit.

```hcl	erraform {
  required_version = ">= 1.0"
}

module "network" {
  source = "./modules/networking"
  vpc_id = "vpc-12345"
}
```

Output from `terraform plan`:
```
Error: Module not found

The module at "./modules/networking" could not be found.
```